A whale-sized asteroid with the potential to release 1 million tons of TNT will zoom safely past Earth next week

Eight days from now a 100-foot-diameter asteroid named "2013
TX68" will fly past Earth for the second time in recorded
history.

One hundred feet is about the size of a blue whale, but to be
clear, 2013 TX68 is not considered a potentially
hazardous asteroid and poses no catastrophic threat to human
life on Earth.

Still, NASA's Center for Near-Earth Object
Studies (CNEOS) has had its eye on this space
rock since it was discovered in 2013.

The NASA-funded Catalina Sky Survey
first spotted 2013 TX68 on Oct. 6, 2013 while it
was passing at a distance of 1.3 million miles away.

Now, according to the latest
updates on the asteroid's location and
orbit, the CNEOS has estimated that
"2013 TX68" will fly past Earth on March 8 at a safe distance of
3 million miles away.

That's a distance of about 12.5 times farther away than the Moon
is from Earth.

Unfortunately for asteroid spotters, this means that we likely
won't have a chance to see the asteroid upon its closest
approach.

"There is no concern whatsoever regarding this asteroid — unless
you were interested in seeing it with a telescope," Paul Chodas,
the manager of CNEOS, said in a press
release. "Prospects for observing this asteroid, which were
not very good to begin with, are now even worse because the
asteroid is likely to be farther away, and therefore dimmer than
previously believed."

Chodas admitted that because this asteroid is hard to spot, the
data on its location is too sparse for the CNEOS to map its orbit
completely. And this does leave a bit of uncertainty about
exactly where the asteroid will be and when.

For instance, there's a small chance that on March 8, 2016, this
asteroid could get as close to our planet as 15,000 miles away.
That's still too far to do any harm, fortunately.

Twice as powerful as the Chelyabinsk event

Even if 2013 TX68 were going to make contact with Earth, an
asteroid this size poses no catastrophic threat to human life.

While it's currently the size of a blue whale, Earth's atmosphere
would make quick work of the asteroid, whittling it down to a
fraction of its current size.

But it could still cause some damage.

For some idea of just how much, NASA calculated what might happen
if 2013 TX68 were to enter Earth's atmosphere.

It would likely generate a radiant fireball that would explode
close to the surface, but before hitting the ground. Such an
explosion is called an air burst, and it's the blast wave from
air bursts like these that can be dangerous.

The Chelyabinsk event in 2013, for example, generated three
different air bursts, the most powerful of which released the
equivalent energy of 500,000 tons of TNT.

2013 TX68 is about twice the size of the asteroid that broke up
over Chelyabinsk, Russia, and NASA calculated that it would
release twice as much energy — or about the same as 1 million
tons of TNT. But, again, the chances of this happening on March 8
are zero.

However, March 8 won't be the last time we hear of 2013 TX68.
It's expected to pass by Earth three more times this century in
2017, 2046, and 2097. But the odds of an impact are slim to none.

CNEOS estimated that the odds of an impact on Sep. 28, 2017 are 1
in 250 million — you have a
far better chance of dying from a lightning strike than from
this asteroid. And the odds of a later impact in 2046 or 2097 are
even lower.